I propose to investigate the interconnections and dynamics of neuronal networks controlling vocalizations of the domestic fowl. Its vocalizations are favorable for analysis because: a) the behavior is simple, rhythmical, and readily recorded; b) control of sounded vs. silent expirations is by only three pairs of muscles; c) the motor commands are centrally programmed so that their activity is readily studied in curarized preparations for stable unit recording; d) vocalizations are important as components of communication and emotional behavior; e) the behavior is under good experimental control even in surgically anesthetized preparations. I will: 1) Analyze the firing patterns of units in the hypoglossal nucleus and adjacent areas during call bursts evoked by electrical stimulation of the midbrain; 2) Compare effects, on activity of these units, of midbrain stimulation with those produced by CO2 in the ventilating air to determine the amount of overlap of respiratory and vocal rhythm generators in the medulla; 3) Compare effects of stimulation of various brain structures known to modify vocalizations, on medullary unit activity 4) Determine the function of the midbrain call region by detailed correlation of call thresholds throughout the midbrain with histology and by recording changes in unit activity there produced by electrical stimulation in other brain areas; 5) Investigate the relationships between calling and other behavior by comparing changes in behavior following muting lesions in the midbrain call area with those produced by medial archistriate (tr. occipitomesencephalicus).